Errors and refusals

Handle the result contract

Invalid input can throw RangeError. A valid request that the calc entry cannot compute returns status refused with a reason and detail. Do not automatically retry invalid data.

import { calc } from '@zodiacs/engine/calc';
try {
  const result = calc({ body: 'Sun', time: '1700-06-01T12:00:00Z' });
  if (result.status === 'refused') {
    console.log({ reason: result.reason, detail: result.detail });
  }
} catch (error) {
  if (!(error instanceof RangeError)) throw error;
  console.log('Invalid input; correct the request before retrying.');
}

Typed refusal catalogue

unsupported-combination identifies an unsupported combination; not-in-this-version identifies a capability this entry does not offer. out-of-range carries the instant span. epoch-out-of-range carries the permitted precession epoch span. sample-budget carries samples and maxSamples.

A linear ayanamsa and a precession-carried ayanamsa have different epoch rules. A hosted HTTP failure is a separate envelope and status code: preserve Retry-After for rate limits, and never treat a refusal as a successful numerical result.

Install the release

npm install @zodiacs/engine@1.0.0

npm's 1.0.0 tarball is byte-identical to the archive the engine repository carries. To install those bytes from the carrier, with their digest checked before npm sees them, run this in the project's directory instead:

( set -eu
# POSIX shell — macOS, Linux or WSL. Not PowerShell. It runs in a subshell, so
# a failure stops the install without closing your terminal.
BASE=$(pwd)
FILE='zodiacs-engine-1.0.0.tgz'
# Run it in your project's directory. Without a package.json here, npm would
# install into the nearest parent directory that has one.
if test ! -f package.json; then
  echo "Stop: there is no package.json here. Run this in your project's directory, or create one first with: npm init -y" >&2
  exit 1
fi
if test -e "$FILE" || test -L "$FILE"; then
  echo "Stop: $FILE already exists here. Move or delete it, then run this again." >&2
  exit 1
fi
# A download that fails verification is removed, so the guard above does not
# then block the retry. Once npm takes over the archive stays: npm reports its
# own failures, and the file is what you would retry with.
trap 'status=$?; if test "$status" -ne 0; then rm -f "$BASE/$FILE"; fi; exit $status' EXIT

curl --disable --fail --silent --show-error --location --proto '=https' --max-time 120 \
  'https://raw.githubusercontent.com/zodiacs-org/engine/38d31854e5716454921b6ce8a211788a0984328e/artifacts/zodiacs-engine-1.0.0.tgz' -o "$FILE"

node --input-type=module <<'JS'
import { readFileSync } from 'node:fs';
import { createHash } from 'node:crypto';
const file = 'zodiacs-engine-1.0.0.tgz';
const expected = 'c4d3754de899fb98882331e6d7b9ce3ce77fb2072baeb002aa0ef8c77b0ab0f6';
const bytes = readFileSync(file);
const actual = createHash('sha256').update(bytes).digest('hex');
if (actual !== expected) {
  console.error(`Stop: this is not the published archive.\n  expected ${expected}\n  got      ${actual}`);
  console.error('Nothing was installed.');
  process.exit(1);
}
console.log(`Archive verified: ${actual}`);
JS

trap - EXIT
npm install --ignore-scripts "./$FILE"
echo "Installed @zodiacs/engine@1.0.0 from the verified archive."
)

References

• Engine source reference
• Hosted error catalogue